Weylus lets you use your tablet as input device on your computer. The screen is mirrored and things like pressure sensitivity as well as multi touch is supported. Like this you can easily start drawing or handwriting on your computer using your tablet.
Weylus only needs to be installed on your computer, NO apps are required! You can just connect your tablet to your computer via browser.
Yes you are right, input lag is definitely lower. I don’t have numbers though as it is kinda hard to measure.